I have booksapp on my Android phone. You can import a .csv into it. So I took the old list and put it into the booksapp format (in excel on a computer) and imported it to my phone (via email). I intend at some point to merge the updated booklist into my current booksapp .csv
Hope that helps!

(I keep track of which books I own by having a collection in booksapp called "got it".)

(I expect you could do a similar thing with other online library keepers or apps)

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Tasmanian mum and nurse sharing one of God's garden beds with four other 'Son-flowers' - DH (husband of 15 years), Little Bear (DS 11yo Y4), Miss Muffet (DD 9 yo Y4) and Mouse (DS 6yo y1!)."A child of any age should be a well-read person for his age." - Charlotte Mason